Japanese Patent No. 4985639 discloses an ink jet printer as an example of a liquid ejection device. The printer includes: an ink jet head (a liquid ejection section) ejecting ink; and a buffer tank (a liquid supply section) arranged above the ink jet head and supplying the ink to the ink jet head. The ink jet head and the buffer tank are mounted on a carriage moving in the scanning direction and hence move in the scanning direction together with the carriage.
The ink jet head includes four ink introduction ports (supply ports) through which inks of four colors (black, magenta, yellow, and cyan) are supplied respectively. Here, one ink introduction port is provided for black ink and one ink introduction port is provided for magenta ink. However, two ink introduction ports are provided for yellow ink and two ink introduction ports are provided for cyan ink. That is, the ink jet head includes a total of six ink introduction ports. Then, the six ink introduction ports are aligned in the scanning direction of the ink jet head.
The buffer tank is connected to four ink tanks through tubes. Then, the inks of four colors are supplied from the four ink tanks to the buffer tank. The buffer tank includes six air-liquid separation chambers respectively corresponding to the six ink introduction ports of the ink jet head. Here, two air-liquid separation chambers are provided for yellow ink and two air-liquid separation chambers are provided for cyan ink similarly to the ink introduction ports. Then, each two air-liquid separation chambers into which ink of the same color is introduced are in communication with each other. Further, the six air-liquid separation chambers are aligned in the scanning direction of the ink jet head in correspondence to the six ink introduction ports. The ink supplied from each ink tank to the buffer tank flows into the air-liquid separation chamber. Here, in a case that air is mixed in the supplied ink, when the ink flows from the air-liquid separation chamber toward the ink introduction port of the ink jet head located thereunder, the air mixed in the ink is separated from the ink and then collected in the upper portion of the air-liquid separation chamber. Thus, the ink in the buffer tank is supplied to the ink jet head after the air is separated and removed in the air-liquid separation chamber.